Pressure vessels useful for a variety of applications have long been made from synthetic resinous materials, such as epoxy resins, acrylic resins and polyurethane resins. Such vessels are frequently provided with adequate strength to withstand high internal pressure by the employment of fiber reinforcement, e.g. windings of continuous filaments. Pressure vessels of this type have found significant use in ultrafiltration (UF), reverse osmosis (RO), nanofiltration (NF), microfiltration (MF) and other types of fluid separation or filtration systems wherein a feedstream is being separated into a permeate or filtrate stream and a concentrate stream. Such applications often require one or both ends of the pressure vessel to have full bore access for the insertion/removal of separation cartridges having generally right circular cylindrical shape, and such pressure vessels have advantageously been fabricated by winding on cylindrical mandrels.
U.S. Pat. No. 5,305,601 illustrates providing resin-impregnated fibrous rovings containing long lengths of continuous filaments and winding them about a rotating mandrel or other body, or alternatively feeding them through a shaping die, to form a tubular article that may be used as a part of a solid fuel rocket motor assembly. The patent illustrates state-of-the-art filament-winding systems which are commercially available, and the disclosure of the patent is incorporated herein by reference.
U.S. Pat. No. 5,772,938 shows making a storage tank by winding discrete fibrous bundles of filaments onto a mandrel using apparatus which applies a viscous resinous material either interior of or exterior of a helical wound layer of such bundles, followed by curing to form a hollow cylindrical structure.
Even with apparatus of the types depicted in these patents, methods for making fiber-reinforced pressure vessels having full bore access have heretofore been relatively labor-intensive and unfortunately have frequently resulted in the production of significant percentages of vessels that failed to meet initial quality control inspection. As a result, there has long been a desire to search for improved manufacturing methods for making pressure vessels of this general type.